In operation of a gas turbine engine, air at atmospheric pressure is initially compressed by a compressor and delivered to a combustion stage. In the combustion stage, heat is added to the air leaving the compressor by adding fuel to the air and burning it. The gas flow resulting from combustion of fuel in the combustion stage then expands through a turbine, delivering up some of its energy to drive the turbine and produce mechanical power.
In order to more efficiently drive the turbine, the gas flow from the combustor is directed against the turbine blades at a given angle and flow rate. Thus, a nozzle having a preestablished size and shape is positioned intermediate the combustor and the turbine. Furthermore, the size and shape of the nozzle will determine the flow characteristics of the gas flow and the resulting efficiency and/or power output.
For example, traditionally the nozzles have either been air or water flow tested to predict the in service performance. However, the hardware is very expensive, a fixture would have to be fabricated for each different nozzle configuration, the system was very large and made field testing impossible and the noise levels could easily exceed safety standards making ear protection and wall insulation mandatory.
Attempts have been make to physically measure the nozzle openings area and then develop a correlation between the area and the service performance. However, such gages are very expensive and require a separate gage for each nozzle configuration making the total cost similar to that of air and water flow testing. Furthermore, these physical measuring gages have wear problems which limits the accuracy to the physical measurement.
The present invention is directed to overcome one or more of the problems as set forth above.